ELF: Remove the function SymbolTable<ELFT>::findFile.

We already have the function SymbolBody::getSourceFile which does the same thing.

llvm-svn: 268353
diff --git a/lld/ELF/Writer.cpp b/lld/ELF/Writer.cpp
index 093fac8..7a4ec04 100644
--- a/lld/ELF/Writer.cpp
+++ b/lld/ELF/Writer.cpp
@@ -785,7 +785,7 @@
   }
 
   std::string Msg = "undefined symbol: " + Sym->getName().str();
-  if (InputFile *File = Symtab.findFile(Sym))
+  if (InputFile *File = Sym->getSourceFile<ELFT>())
     Msg += " in " + File->getName().str();
   if (Config->NoinhibitExec)
     warning(Msg);